Use of proprietary software on an untrusted computing device may lead to unauthorized copying or manipulation of the proprietary software. Some makers of proprietary software encrypt the software so that when it is stored on an untrusted computing device, the software can only be decrypted if the computing device has access to a trusted security device that has a suitable decryption key or code. The decrypted proprietary software can then be used by the untrusted computing device. In such cases, the security device that enables decryption and use of the proprietary software is sometimes referred to as a “dongle”.
Thus, when the proprietary software is executed, it uses the dongle to decrypt itself. At various points in the execution of the proprietary software, the software may double-check that the dongle remains coupled to the computing device executing the software. Use of a dongle in this manner has some drawbacks, however. For example, if the computing device on which the proprietary software executes is compromised, it is possible that an unauthorized entity may be able to retrieve the unencrypted image of the proprietary software from the memory of the computing device. Further, it may be possible to fool the software into falsely recognizing the presence of the dongle by changing some instructions in the executable binary code used to check the presence of the dongle.
It is desirable to address or ameliorate one or more drawbacks, disadvantages or shortcomings associated with existing authorization methods and/or security devices, such as dongles, or to at least provide a useful alternative thereto.